PEORIA, Ariz. -- Rockies infielder Jonathan Herrera wore down as last season progressed. Herrera's average plummeted from .287 on May 19 to .242 when he was shut down on Sept. 6 with a fractured right index finger.

But the reasons might go deeper than those one would suspect.

Last year, an outdated roster listing had Herrera at just 150 pounds, making him the Majors' second-lightest player. He's really closer to 185, but even at that weight -- and at 5-foot-9 -- his size was one of the reasons it took him nine seasons to get a shot at a full year in the bigs.

However, even the biggest, most strapping fellow would have had a hard time bearing some of what weighed on Herrera's mind last season.

While Herrera was realizing his big league dream, his mother, Dainys, saw her condition worsen in her fourth year of a battle against cancer back in Venezuela.

"It was a tough year," Herrera said. "A lot of things are in your mind. It's really hard to keep focused and keep playing, or do the things you're supposed to do. Your mom is really sick back home in Venezuela, and you're here.

"She had it for the last four years, but she was OK. Then she got worse as the year went on. She couldn't even be the same person. The whole year she was in back and forth between home and the hospital, then she got worse."

Herrera's mother succumbed on Nov. 20, and all Herrera could do after that was rest. Herrera is a regular participant in the Venezuelan Winter League and Caribbean World Series, but not this past season.

"I didn't have the opportunity to focus and think about baseball," Herrera said. "I told myself that was a good moment to shut it down, concentrate and get ready for this year, Spring Training, fighting for my spot on the team."

Herrera has consistently made his case in a competition for backup infield spots that includes catcher/infielder Jordan Pacheco, Chris Nelson (who could emerge as the starting third baseman should Casey Blake not prove healthy enough coming off neck surgery), Brendan Harris and Brandon Wood.

During Tuesday night's 10-6 loss to the Padres in Peoria, Herrera started at second base and delivered a two-run triple in the fourth inning and scored on DJ LeMahieu's squeeze bunt. Often coming off the bench the way he would as a utility backup, Herrera is hitting .432 with four doubles and five RBIs in 12 games.

"He's a solid baseball player, a thinking man's baseball player," Rockies manager Jim Tracy said. "He's always aware of what the situation is when he walks up to home plate."

Last year, the Rockies intended to make Herrera a utility player who could start in long stretches. But with Ian Stewart struggling through injuries and slumps at third base, and with fellow infielders Jose Lopez and Ty Wigginton not producing consistently, Herrera was forced into more duty than Tracy wanted.

Herrera, however, believes he can handle regular duty if necessary.

"The beginning of the season was really good for me," he said. "I did a really good job in the beginning for two months. Then in the middle, a lot of things happened. So hopefully this year I will be healthy all year long and I can do my best, try to do the job I did at the beginning of last year.

"People say that if you're not that tall or you don't have too much weight, you get tired. You can see lots of big leaguers that area really skinny and they play all the time. I'd like an opportunity to show I can play 150 games in a season."